MOLECULAR TAGGING OF FIBER YIELD GENES USING INTRASPECIFIC R1 LINES OF G. HIRSUTUM DEVELOPED IN UZBEKISTAN

Authors: ABDURAKHMONOV, I - ACAD OF SCI,UZBEKISTAN; BURIEV, Z - ACAD OF SCI,UZBEKISTAN; Saha, Sukumar; MUSAEV, J - ACAD OF SCI,UZBEKISTAN; ALMATOV, A - ACAD OF SCI,UZBEKISTAN; PEPPER, A - TEXAS A&M UNIVERSITY; REDDY, O - TEXAS A&M UNIVERSITY; Jenkins, Johnie; ABDULLAEV, A - ACAD OF SCI,UZBEKISTAN; ABDUKARIMOV, A - ACAD OF SCI,UZBEKISTAN

Submitted to: World Cotton Research Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 3/9/2003
Publication Date: 5/1/2004
Citation: Abdurakhmonov, I., Buriev, Z., Saha, S., Musaev, J., Almatov, A., Pepper, A.E., Reddy, O.U., Jenkins, J.N., Abdullaev, A., Abdukarimov, A. 2004. Molecular tagging of fiber yield genes using intraspecific R1 lines developed in Uzbekistan. World Cotton Research Conference Proceedings. p. 320-326.

Interpretive Summary: Little information is availble concerning the number and the nature of the genes responsible for important fiber traits in cotton. The knowledge of genes and their relationship to the fiber development is important to develop breeding strategies. DNA markers linked to fiber traits will help breeders to expedite the progress in breeding by selecting for the genotype (DNA marker) than on the phenotype which is controlled by complex quantitative trait. Recently we have developed a new class of genetic markers known as EST-SSR markers that are highly polymorphic and provide information about their biological role in growth and development. We initiated new research on molecular mapping of fiber genes using intraspecific recombinant inbred lines of Gossypium hirsutum, developed from the cross of fuzzless/lintless (L70) and fuzzy/linted (L47) lines via SSR technology (SSRs and EST-SSRs). RI lines were grown in field stations of IG&PEB at Uzbekistan and phenotypically analyzed. Leaf tissues were collected and genomic DNAs were isolated from each RI individuals co-segregating for lint yield and fuzz formation as well as cottonseed weight. Parental genomic DNAs were genotyped with EST-SSR markers. Fourteen fiber specific EST-SSR primer pairs out of 85 showed polymorphic PCR-products between parental lines. These polymorphic EST-SSRs were subjected to genotype RI individuals to identify relationship with the fiber QTLs. Single marker analysis revealed that four markers - EST-17, EST-47, EST-32, and EST-56 were highly significant(KW=4.8, 6.8, 13.1, 13.5 respectively). Statistically significant two QTL regions controlling lint percent coincided with the two EST-SSR markers that expressed the highest single marker analysis (SMA) linkage associations, EST-32 and EST-56. EST-32 marker was significantly linked to lint percent and had a LOD of 4.28 explaining 48.1% of variation of lint percentile. The second marker EST-56 also was highly significant and showed a LOD of 4.34. Lint percentile QTL near the locus EST-56 explained 48.6% of variation of the trait. As per our knowledge this is the first report on a PCR-based EST marker associated with fiber gene(s). This research is a collaborative effort between Uzbekistan and USDA/ARS scientists of ARS Former Soviet Union Scientific Cooperation Program to enhance the cotton germplasm, a major economic crop in both countries. Outcomes of this research will accelerate incorporation and rapid deployment of improved agronomic fiber genes into elite cultivars through marker assisted selection programs.

Technical Abstract: In Uzbekistan we have nearly 17,000 cotton germplasm collections including isogenic, inbred lines, elite AD allotetraploid varieties (G. hirsutum and G. barbadense), primary monosomic and translocation lines along with wild, primitive and extant representatives of the A to G genome groups that have been developed in the Cotton Research Institutes of the Republic and collected over the world for the past century. In this germplasm, cotton accessions represent a very useful agronomically important trait, such as insect and pathogen resistance, tolerance to environmental stresses, fiber quality (length, strength and lint yield) and yield potential. There are recombinant inbred and isogenic lines within the collection, widely segregating for lint yield, seed fuzz formation, and seed weight, which will be very useful for molecular analysis of fiber yield genes and fiber QTL-mapping efforts using DNA marker technology. We initiated a new research on molecular mapping of fiber yield genes using RI lines developed from the cross of fuzzless/lintless (L70) and fuzzy/linted (L47) lines via molecular marker technology (SSRs and EST-SSRs). RI lines were grown in field stations of IG&PEB and phenotypically analyzed. Leaf tissues were collected and genomic DNAs were isolated from each RI individual co-segregating for lint yield and fuzz formation as well as cottonseed weight. Parental genomic DNAs were genotyped with microsatellite markers from the JESPR, CM and BNL and EST-SSR collections for potential polymorphic markers. 14 fiber specific EST- SSR markers out of 85 showed polymorphic PCR-products between parental lines. These polymorphic EST-SSRs were subjected to genotype RI individuals to identify fiber QTLs. Single marker analysis revealed that four markers - EST-17, EST-47, EST-32, and EST-56 were highly significant (KW=4.8, 6.8, 13.1, 13.5 respectively). Statistically significant two QTL regions coincided with the two EST-SSR markers that expressed the highest single marker analysis (SMA) linkage associations, EST-32 and EST-56. EST-32 marker was significantly linked to QTL and had a LOD of 4.28 explaining 48.1% of variation of lint percentile. The second marker EST-56 also was highly significant and showed a LOD of 4.34. Lint percentile QTL near the locus EST-56 explained 48.6% of variation of the trait. This research is a collaborative effort between Uzbekistan and USDA/ARS scientists of ARS Former Soviet Union Scientific Cooperation Program to enhance the cotton germplasm, a major economic crop in both countries. Outcomes of this research will accelerate incorporation and rapid deployment of improved agronomic fiber genes into elite cultivars through marker assisted selection programs.